1. Field of the Invention
The present invention relates to a hydraulic unit of an electronic control brake system of an automobile, and more particularly, to a hydraulic unit of an electronic control brake system capable of optimally forming oil lines connecting components and valves which are mounted in a modulator block.
2. Description of the Related Art
An electronic control brake system efficiently prevents wheels from slipping while braking, rapid starting or rapid accelerating of an automobile. Such an electronic control brake system generally includes a booster, a master cylinder, wheel cylinders, a hydraulic unit to control a braking hydraulic pressure, and an electronic control unit (ECU) to control the hydraulic unit.
The hydraulic unit includes a plurality of solenoid valves (inflow and outflow valves) to control a braking hydraulic pressure transmitted to the wheel cylinders, an accumulator to temporarily store oil discharged from wheel brakes, a pair of oil pumps which are driven by a motor, shuttle valves mounted on suction lines of the oil pumps, and traction control valves mounted on discharge lines of the oil pumps. These components are mounted inside a modulator block, which is made of aluminum.
The conventional modulator block has a hexahedral shape. Master cylinder connecting parts and wheel cylinder connecting parts are mounted to a top surface of the modulator block. The inflow valves, the shuttle valves/the oil pumps/the motor, the outflow valves, and the traction control valves are arranged in order from the above in the modulator block.
By such arrangement, a distance between the master cylinder and the shuttle valves is short. However, there are problems such that oil lines connected from the master cylinder to the shuttle valves, the oil pumps, the traction control valves and the wheel cylinders become long and complicated, and accordingly many holes (e.g., eight holes) should be provided to form the oil lines inside the modulator block.
Further, in the above arrangement, because the master cylinder connecting parts and the wheel cylinder connecting parts are disposed at the same surface (i.e., the top surface of the modulator block), there is a limitation in decreasing a width of the top surface. Still further, because the motor to drive the oil pumps is disposed in a lower portion of the modulator block, in which the shuttle valves and the oil pumps are disposed, a size of the modulator block becomes unnecessarily large.